Development of centrifugal precipitation chromatography has been continued. A preparative centrifugal precipitation chromatographic system recently developed by inserting a dialysis tubing into a long convoluted tubing has various shortcomings such as the dialysis membrance is fragile and easily damaged and the result of the experiment is not reproducible since the dialysis tubing changes its volume according to a subtle change of column pressure. Furthermore, the scaling-up by increasing the diameter of tubing the ratio between the membrane surface and the total volume is sharply decreased, resulting in reduction of a relative mass transfer rate through the membrane. In order to improve the efficincy of the mass transfer through the membrane, I decided to use multiple pieces of hollow fiber filter (HFF) tubing inserted into a long piece of standard plastic tubing. I found that such a dialysis device is already commercially available through two companies, although the length of the unit is limited to several centimeters to slightly over one meter. In the first trial, I used 8 units of short HFF tubes of 6.5cm long and 3 mm ID (Spectrum) which are interconnected with Tygon tubing and mounted at the periphery of an aluminum rotary plate. The test run showed that the protein samples tended to delay in their elution probably due to the accumulation of the precipitates at the junction. Therefore, I used a single piece of much longer HFF of 110 cm (Amersham Biosciences) which is mounted on an aluminum rotary plate in a spiral fashion. Although the result of the pilot studies show some promising results, the centrifuge system was damaged. I am now waiting for the repair of the loosened stationary miter gear and damaged ball bearings.